Assessment of uncertainties for the GHP apparatus in determining U-value of double-glazed window with inter-pane blinds

Abstract This paper describes a procedure for determining the component uncertainties for the guarded heater plate apparatus – developed to compute from the measured thermal resistance – the ‘Unit heat loss rate’ of a double-glazed window with inter-pane venetian blinds. An example for computation of such uncertainties as per full-factorial design (162 trial runs) is also presented. The overall uncertainty for determining this U-value was determined to vary from 1.2% to 2.6% for the identified design. It was concluded that the fabricated apparatus has the advantage of getting an acceptable level of accuracy without using the complex and specifically designed equipment.